ALD of Hafnium Oxide Thin Films from Tetrakis(ethylmethylamino)hafnium and Ozone

Liu, Xinye; Ramanathan, Sasangan; Longdergan, Ana; Srivastava, Anuranjan; Lee, Eddie; Seidel, Thomas E.; Barton, Jeffrey T.; Pang, D.; Gordon, Roy G.

doi:10.1149/1.1859631

Cited by 185 publications

(146 citation statements)

References 9 publications

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“…For HfO x , atomic layer deposition (ALD) is often the tool of choice due to the self-limiting growth regime allowing a uniform, stoichiometric and well controlled layer to be deposited [11][12]. When trying to alter the oxygen concentration however, an increase in oxygen flow rate does not necessarily result in an increase in oxygen due to the selflimiting growth reaction.…”

Section: Introductionmentioning

confidence: 99%

The effect of atomic layer deposition temperature on switching properties of HfOx resistive RAM devices

Morgan

Huang

Pearce

et al. 2014

2014 IEEE International Symposium on Circuits and Systems (ISCAS)

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Abstract-TiN/HfOx/TiN resistive RAM (RRAM) devices have been fabricated where the hafnium oxide layer has been deposited at three different temperatures via atomic layer deposition (ALD). Material characterization shows the structure of the hafnium oxide is converted from cubic to monoclinic for 400 degrees C. Elemental analysis shows that the temperature affects the stoichiometric behavior of hafnium oxide, with a higher oxygen concentration at 350 degrees C and above. The switching behavior differs significantly for each device whereby the 400 degrees C device shows no successful switching, due to the change in structure to monoclinic. The two lower temperatures both show successful bipolar switching which set at negative voltages. The 300 degrees C device has a higher Roff/Ron of 13.9, with superior endurance. The 350 degrees C device has a lower Roff/Ron of 5.5 and shows deterioration in switching properties as the number of cycles are increased. At 300 degrees C, the oxygen hafnium ratio is at a minimum; hence the greatest amount of oxygen vacancies are present, which results in improved switching characteristics. This supports the theory that oxygen vacancies play a key role in the switching mechanism for metal oxide RRAM devices.

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Section: Introductionmentioning

confidence: 99%

The effect of atomic layer deposition temperature on switching properties of HfOx resistive RAM devices

Morgan

Huang

Pearce

et al. 2014

2014 IEEE International Symposium on Circuits and Systems (ISCAS)

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“…Furthermore, for some materials it has been reported that improved film properties are obtained when using O 3 or O 2 plasma instead of H 2 O. [2][3][4][5][6][7][8] The potentially more favorable process settings ͑e.g., in terms of substrate temperature and purge times͒ as well as the potentially improved material properties obtained for the O 3 and O 2 plasma based ALD processes have also contributed to an increased interest into ALD by other fields of technology than semiconductor industry. Potential application of ALD films in areas such as microsystems, solar cells, flexible electronics, energy storage, and photonics have recently been reported.…”

Section: Introductionmentioning

confidence: 99%

Reaction mechanisms during plasma-assisted atomic layer deposition of metal oxides: A case study for Al2O3

Heil

Hemmen

Sanden

et al. 2008

Journal of Applied Physics

109

111

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Plasma-assisted atomic layer deposition ͑ALD͒ of metal oxide films is increasingly gaining interest, however, the underlying reaction mechanisms have rarely been addressed. In this work, a case study is presented for the plasma-assisted ALD process of Al 2 O 3 based on Al͑CH 3 ͒ 3 dosing and O 2 plasma exposure. A complementary set of time-resolved in situ diagnostics was employed, including spectroscopic ellipsometry, quartz crystal microbalance, mass spectrometry, and optical emission spectroscopy. The saturation of the Al͑CH 3 ͒ 3 adsorption reactions was investigated, as well as the reaction products created during both the precursor dosing and the plasma exposure step. The generality of the observations was cross-checked on a second commercial ALD reactor. The main observations are as follows: ͑i͒ during the precursor dosing, the Al͑CH 3 ͒ 3 predominantly binds bifunctionally to the surface at 70°C through a reaction in which H is abstracted from the surface and CH 4 is released into the gas phase; ͑ii͒ during the plasma exposure, O radicals in the plasma are consumed at the surface by combustionlike reactions with the surface −CH 3 ligands, producing mainly H 2 O, CO 2 , and CO; ͑iii͒ small gas phase densities of CH 4 and higher hydrocarbons ͑C 2 H x ͒ are also present during the O 2 plasma exposure step indicating complementary surface reactions including a secondary thermal ALD-like reaction by the H 2 O produced at the surface; ͑iv͒ the plasma and its optical emission are strongly affected by the surface reaction products released in the plasma. In the latter respect, optical emission spectroscopy proved to be a valuable tool to study the surface reaction products during the plasma exposure as well as the saturation of the surface reactions. The implications of the experimental observations are addressed and it is discussed that the reaction mechanisms are generic for plasma-assisted ALD processes based on metal organic precursors and O 2 plasma as oxidant source.

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“…ALD recipes for Al 2 O 3 came from Goldstein, 10 MgO from a custom reaction developed at JPL by the authors, SiO 2 from Dingemans 12 and HfO 2 from Liu. 13 Often growth recipes required modifications to accommodate the equipment used. Modified growth recipes were typically validated using either XPS, TEM, or both.…”

Section: Deposition Techniquesmentioning

confidence: 99%

UV photon-counting CCD detectors that enable the next generation of UV spectroscopy missions: AR coatings that can achieve 80-90% QE

Hamden

Greer

Schiminovich

et al. 2012

High Energy, Optical, and Infrared Detectors for Astronomy V

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We describe recent progress in the development of anti-reflection coatings for use at UV wavelengths on CCDs and other Si-based detectors. We have previously demonstrated a set of coatings which are able to achieve greater than 50% QE in 4 bands from 130nm to greater than 300nm. We now present new refinements of these AR-coatings which will improve performance in a narrower bandpass by 50% over previous work. Successful test films have been made to optimize transmission at 190nm, reaching 80% potential transmission.

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ALD of Hafnium Oxide Thin Films from Tetrakis(ethylmethylamino)hafnium and Ozone

Cited by 185 publications

References 9 publications

The effect of atomic layer deposition temperature on switching properties of HfOx resistive RAM devices

The effect of atomic layer deposition temperature on switching properties of HfOx resistive RAM devices

Reaction mechanisms during plasma-assisted atomic layer deposition of metal oxides: A case study for Al2O3

UV photon-counting CCD detectors that enable the next generation of UV spectroscopy missions: AR coatings that can achieve 80-90% QE

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